Typical indoor units for air-conditioning apparatuses are each provided with an up-down airflow direction plate in an air outlet to adjust the flow of air blown off from the air outlet. As one of such indoor units for air-conditioning apparatuses, an indoor unit that includes a fan arranged in an airflow passage extending from an air inlet to an air outlet, a heat exchanger arranged around the fan, and an up-down airflow direction plate and an auxiliary airflow direction plate extending along the longitudinal direction of the air outlet, the up-down airflow direction plate being formed as one flat plate, is disclosed (see Patent Literature 1, for example).